Centerless grinding machine



Fab. 1 9

. 'I';6I6,'29 6 w. A. ADDIS CENTERLESS GRINDING MACHINE Filed June 10, 1924 s Sheets-Sheet 2 1 9 w. A. ADDIS GENTERLESS GRINDING MACHINE v 3 Sheets-Sheet 5 Filed June 10, 1924 INVENTOR ATTORNEY Patented Feb. 1, 1927.

' UNITED STATES 1,616,296 PATENT OFFICE.

vvmrnrzm. ADDIS, or GREENFIELD, MASSACHUSETTS, ASSIGNOR CTO GREENFIELD TAP AND DIE conrormrrou, or GREENI-IELD, MASSACHUSETTS, A conrona'rron or MASSACHUSETTS.

CENTERLESS GRINDING MACHINE.

Application filed an 10, 1924. Serial no. 719,032.

This invention relates to centerless grinding machines, and the principal aim of my invention is to provide a centerless grinding machine with which drills or other cylindrical work maybe ground mechanically and automatically to have a uniform back taper of any desired amount within certain limits, and to provide a machineadapted for expeditious quantity production of work having the utmost precision and uniformity. A further object of my invention is to provide a machine of the above character adapted for high speed operation, and adapted to operate efiiciently, quickly and with a minimum of expense. A further object of my invention is to provide improved means for automati- Cally" feeding successive units of. work' through the machine. Another object of my inventionis to provide improved means for taking each unit of the work against the abrasive wheel so as to be ground in the man-' ner desired. Another object of my invention is to-provide means whereby'the machine may be adjusted readily and easily for different sizes of work. Other objects of my invention will be in part obvious and in part pointed out hereinafter.

My invention accordingly consists in the features of construction,combinations of elements, and arrangement'of parts which will be described hereinafter, and the scope of the application ofwhich will be po inted'out in the claims that follow.

In accordance. with my invention, the machine includes a work hopper, constantly open for 'replenislnnent, adapted to dispense units of work, such as metal bars, rods, or

v shafts, singly and successively into position for engagement by automatically reciprocatmg feed means, whereby each unit of work is moved separately and with a continuous forward movement transversely across a grinding means,such as a constantly rotating abrasive wheel, the work during such movement being engaged by positioning means which serve to position and hold "the work againstthe periphery of the grinding wheel to cause the workto be ground. The positioning means include a cam operated work head which receives the work, and the cams gradually and evenly move the work head and the work therein radially away from thegrinding wheel as the. work is moved endwise through the head by the feed means, thereby causing the work to be ground with a uniform back taper per unit -of length. The work head includes upper and lower supporting members and a rear supporting member or back rest, all relatively adjustable on-the head for the proper accommodation of work of different diameters. The back rest for thework preferably includes a roll of abrasive resisting mate-.

rial, and is rotatively adjustable so that dif-' ferent portions of its'surfacelmay be presented to the abrasive action of the rotating work being ground, Without requiring removal of the back rest from themachine nor the removal of the roll from the rest. The cams of the work head moving and positioning means are interchangeable with othercams, permitting the. machine to be adjusted to grind the work to diiferent amounts of hack taper per unit of length, or with no' 7 back taper. The feed means take the form of a'plunger which is continuously reciproferward and return spiral grooves, and whichon its forward stroke pushesa unit of work through the work head and then returns to engage and to advance the next unit of workdispensedby the hopper. The cams which drive the movable work head have a synchronized connection with the drum and its driving means. The hopper is made up of a plurality of relatively adjustable parts so as to be fully. adjustable for work units of different lengths and diameters.

In order thata clearer understanding of my invention may be had, attention is hereby directed to the accompanying drawings, forming a part of this application and illustrating one possible embodiment of my in cated by means of a rotating drum having Fig. 3 is a sectional view taken on the line 2--3 of'Fig. 1, looking in the directiontof the arrows; Fig. 4 is a'sectional view through the work head, and is taken on the line 4-4 oi Fig. 3; Fig. 5 is a sectional view taken on the line 5--.5 of Fig. 1, looking in the direction of the arrows; and Fig. 6 is an enlarged side view partly in Section, and IS in the forwardly for a full stroke durin two revolutions of the drum and then rearwardly taken on the line 6-6 of F ig. 5. Similar reference characters refer to similar parts throughout the several views of the drawings Referring to-the drawings, the machine as a whole is secured firmly upon, a suitable stand or base 1. The machine includes a main driving shaft 2, journaled in suitable brackets 3 and 4, which are bolted 'to the base, the shaft being supplied at one end with a drive pulley 5, preferably of the multiple step'cone type, whereby the machine may be driven atvarious speeds in the usual manner by power from any suitable source. A drum 6 is mounted on shaft 2 for rotation therewith, and in its periphery is a right hand spiral groove 7 making two turns around the drum, and a left hand spiral'groove 8, making a single turn around the drum. These grooves are mutually continuous at each end of the drum, sothat upon every three rotations of the drum a follower 9 engaged grooves will be reciprocated, first to initial position during one revolution of the drum. Follower 9 is a part of a cross head 10' which reciprocates on two slides- 11 secured to, the drum shaft brackets 3 and 4, and a plunger'orpush rod 15 is main portion 17 secured'to this crosshead for reciprocation therewith. A hopper 12 is adapted to dispense units of work, 13, one by one,. to a suitable work centering bed plate. directly 'in advance of push rod 15 when the push rod is in retracted position due, to rotation of drum 6. As the head and push rod then move forward again due to continued rotation'of the drum, the forward end of the rod engages the 'rearend of the unit of work and through a work head which serves to position this unit of work in such enga ement with the periphery of the rotating a rasive wheel 16 that the work will be ground thereby while the ,work is being moved through the head and transversely across the wheel by the push rod 15. The .work

is fully rotatable in the work-head by the grinding wheel. The work head includes a u on which are mounted adjustabl y upper and lower positioning plates, 18 and 19, av-ing oppositely tapered surfaces to center the work, and'a back rest 20 which abuts the work on its side opposite the abrasivewheel and holds the work 7 tend through slots 22 against these tapered surfaces. Plates 18 and '19 are secured to 'theworkhead por-- tion 17 by means of screws ,21 which exprovided in the plates, permitting .the plates to be, adjusted vertically on the work head to accommodate the I head towork of different. diameters.

pushes it endwise into and The operates with plates '18 and 19 to-hold it;

in proper position on the head for engagement against the abrasive wheel 16. Roll 23 is held in position for rotatlve adjustment by pairs of upper and lower clamping plates 24 and 25, and by-a backing block '26 which has a groove 27 in which the roll 23 fits. Block 26 is held on the head by means of screws 28 which extend through slots 29 in the head to permit adjustment of block 26 for different sizes of work and for different amounts of grinding. Such adjustment is effected by means of a slide member '30 which has tapered bosses 3 engaging cooperating tapered surfaces, 32 formed on the rear of member v26. One end 33 of slide 30 extendsfro'n'i the work head and is threaded .so that the slide may be adjusted with respect to the head by means of nut .34 and locknut 35 thereon. "It will be readily apparent that by manIpulatmg screws 28 and nut 34:, the block 26 and the back roll 23 may be moved and locked invarious advanced orretracted positions on the head and with respect to the positioning plates 18 and 19. It is also apparent that the back roll 23 may be revolved readily and easily to bring afresh pol tion of its surface against" the'work,

for each pair of clamping plates 24 and 25 23 by means of.

is clamped against roll screws 36, and when these screws are loosened the roll 23 may be turned into a new position-in which it may be secured by retightening the screws 36. If desired, the

roll 23 may be provided at one end with a groove 37 in which a screw driver or other suitable tool may be engaged to turn the roll when the clamping plates are loosened.

each of these projections is a cam wheel 39 secured to a shaft 40 brackets 41 fastened able springs, siliently hold the work head p rojectons 38 against the periphery of the cam wheels 39', so that as the cams 39'revolvethe work head is moved towa'rd and from the abrawhich is journaled in on the base 1. Suitsive wheel16 in accordance with the con-1 .figuratipnof the cam surfaces of the cams.

Shaft 40 carries on meshes with a gear driving shaft 2, and the ratio between these gears is such thatthe shaft 40 and the cams 39 carried thereby will be given one complete revolution for every three revolutions ofdrum6 back rest 2O includes a cylindrical member I. v The work hopper 12 is constructed ,to be such as 42, constantly. and re- The entire work head is piva-tally sup- 7 one end a gear 42 which 43secured to the inain fully adjustable for various sizes of drills or other work. There is. anangular base 'casting- 44 which is adjustably secured to the machine base 1 by means; of screws 45 which penetrate slots 46 in the casting 44. This casting has a threaded boss 47 in whichis engaged the' threaded -end of a screw 48 which is retainedfor rotation and against." longitudmal movement in a bracket 49 secured to base 1.

A longitudinal angular frame member 50 is supported for vertical adjustment on the vertical wall of casting '44 by means of screws 51 which extend through slots in member 44. Frame 50 may be adjusted vertically by turning a vertical screw 52 which is threaded into member 44 'andwhich has an annular flange 53 constantly engaged beneath a hook 54 attached vto member 50. Member 50 is grooved to accommodatea bar 55 which is provided with a 'V-shaped slot into which the hopper delivers each unit of work andfrom which the plunger 15 takes the work into the work head andthrough the machine. There are two spaced hopper members 56 and 5 7, each having a vertical channel portion 58 in which the opposite ends of a stack of work units are engaged for successive delivery to.

the V-bar 55. The hopper brackets .56'and 57 are adjustable toward and' from each other to accommodate difierent lengths of drills by being secured to member. 50 by .means of bolts 59 which have heads 60 en 'g'aged in a T-slot 61 in the member. 50. A "suitable table portion 62 for Work units may be associated with and 57.

5 The operation the hopper members 56 0f the-machine is as 01- lows :-:'-The main driving shaft is driven .constantlyrata. suitable speed-by means of power applied to the'pull'ey 5. After the opper and the work head have been suitably adjusted for the particular size of work-which is to be ground, and after the 'workfhead has also been properly adjusted for the particular size of grindmg and degree of taper desired to be glven to the work by the machine, it is only necessary to coni tinuously feed the work into the hopper, and I the work'will be delivered automatically and mechanically in successive units from the end of the machine in finished condition. It

; will be a-pparent that as the main drive shaft 2 rotates the push rod 15 pushes a unit of workygfrom the hopper, where it has-been centered by the V-shaped slot in the member 55,, and through the workhead between the plates18 and 19 and between'the abrasive wheel16 and the work rest roll 23. As the rod 15 moves the work into the work head with an even uniform rate, the cam wheels39 havelmoibed the work head up to its near- -est;position to the abrasive wheel 16. the work passes by 2the face of the abrasive wheels the work'head backs away from the face of the abrasive wheel, due to springs 42 causingthe work head to follow the dropping of the surfaces of the cams 39, and due to this retraction of the work relative to the abrasive Wheel during grinding and while the work is mo ved along, the work is caused to be ground with a back taper. As this rod 1 5 isretracted to'initial position to engage another unit of workpthe earns 39 advance the work head into its original position The gearing connections between the drum 6 and the cam shaft 40 result in exactsynchronism in movement between the feeding and positioning mechanisms of the machine. Different degrees of back taper may be ground by merely changing the cams 39 for others of different cut. Obviously the camsmay-be so designed that no taper is givento the work.

- As many changes could be made in the M above construction and many different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as i-llustra-' tive and not in'a limiting sense.

What I claim is: I p 1. In a rinding machine of the characterdescribed, m combination, a rotary grinding wheel having an'abrasive periphery, feed means for moving a unlt of work across the periphery of said wheel, and positioning means for moving said work -1I1 a radial direction graduall away from said wheel during the entire movement of a predetermined portion of the work across the grinding wheel, whereby said portion of the work is ground with a cylindrical taper, said positioning means holding the work loosely, and

groundjvith acylindrical taper, said feed 4 and positioning means having synchronized movement one with'zthe other, said position ing means holding the work loosely-and the work being rotated by-said grinding wheel.

3. In a grinding machine of the'character described, in combination, a rotary grinding wheel having an abraslve periphery, feed means for moving a unit of work across the periphery of said. wheel, and positioning. means for moving said work in aradial direction gradually away a-from; saidwheel during the entire;.movem nt of a predetermined portion of; the Work across the grindingwheel, whereby said portion of the, work is ground with a cylindrical taper, said feed means including a reciprocating rod engaging the work endwi'se, and said positioning meansincluding a reciprocating head engaging the work transversely. Y

4. In a grinding machine of thecharacter described, in combination, a rotary wheel having an abrasive periphery, movable feed,- means for movin a unit of work across the periphery of said wheel, and movable. posi tioning means adapted, duringsuch movement of the work, to take the work into varying engagement against said Wheel,

7 whereby the work is ground with a taper,

said feed means including a reciprocating work advancing member, saidpositioningmeans including a reciprocating Work holding member, and means for moving said Work advancing member and said work holding member in synchronism with each other..- 5. In a grinding machine of the character described, in combination, a rotary wheelhaving an abrasive peripher movable feed means for moving a unit of work across the peripheryof sa'idwheel, and movablepositiomng means adapted, during such move-' ment-of the work, to take the work into varying engagement against saidwheel, whereby the work is ground with a taper, said positioning means holding theework for rotation by said grinding wheel during the grinding operation.

6. Ina machine of the character described,

- means for operating upon work fed through 'feeding work through the machine, and pothe machine, and means for feeding Work through the machine, said feed means in-. cluding a revolving drum having'continuous forward and return spiral grooves, a folengaging reciprocation by the revolution drum.

7. In amachine of the character described, 111 combination, grinding means, mea'ns'for of said sitioning means for taking work fedby said feed means into operative engagement with said grinding means, said ositioning means including a movable -wor accommodating head and associated mechanism, including a cam, determining the position. and move-. ment of said head. I j

8. In a machine of the character described, in combination, grinding means, means for 1 feeding w'orkthrough the machine, and positioning means for taking work fed by. said feed means into operative engagement with said grinding means, said positioning means in"combination, grinding means, means for.

feeding work through the machine, and p0 sitioning means for taking work fed .by said iced means into operative engagement with said grinding means, said positioning means including upper and lower spaced Aposition ing plates and a back rest, cooperating to provide'a passage through which a unit of. work may be movedendwise with a-lateral' portipn of the work-protindingtransversely from between said upper and lower plates, and permitting said work to rotate on .its longitudinal axis, said back rest in-? cluding a roll of abrasive resistant material and clamping means 'maintaining said roll inposition on said back rest,said clamping means being. adjustable to'permit said roll to be adjusted rotatively on said back rest, whereby diflerent portions of its surface in the head.

'10. In a machine of the character, de-'. scribed, ahopper adapted to dispense units.

may be presented for engagement bywork of work separately 'for feeding through the lll machine,'-said hopper comprising, in combination, a base member mounted for hori zontal adjustment on the machine, a hori-' zontal member mounted for vertical ad.-

justment on said base member, and upright w'ork guiding standards mounted for indeorizontal member. 4 11. In a'machine of thei'cha-racter 'de' scribed, 'a hopperadapted to dispense units of 'work separately for feeding:tlirough the machine, said hoppei= "comprising,.in combination, a base membermounted for-horiipendent horizontal adjustment on said zontal adjustment on themachine, a horizontal member mounted for vertical adjustwork-guiding standards amounted for. indem ment on said. base member,- and. upright 7 pendent horizontal-adjustment on said horizontal member, said horizontal -member having. a slot *positioned to freceive work leaving said standards, whereby said work centered for being fed through the machine.

June, 1924,-

This specification signed this 6th day of;

WENDELL n Annls. 

